protected virtual bool ParseArguments(ItemFactory itemFactory, ITextProvider text, TokenStream tokens)
{
if (tokens.CurrentToken.IsFunctionTerminator())
{
// There could be functions without arguments (like "filter: mask();")
return(false);
}
while (!tokens.CurrentToken.IsFunctionTerminator())
{
ParseItem fa = CreateArgumentObject(this, itemFactory, Arguments.Count);
if (fa.Parse(itemFactory, text, tokens))
{
fa.Context = GetArgumentContext(Arguments.Count);
Children.Add(fa);
Arguments.Add(fa);
}
else
{
// Don't know what this is
Children.AddUnknownAndAdvance(itemFactory, text, tokens, ParseErrorType.UnexpectedToken);
}
}
FunctionArgument lastArgument = (Arguments.Count > 0) ? Arguments[Arguments.Count - 1] as FunctionArgument : null;
if (lastArgument != null && lastArgument.Comma != null && lastArgument == Children[Children.Count - 1])
{
Children.AddParseError(ParseErrorType.FunctionArgumentMissing);
}
return(true);
}
/// <summary>
/// This helps the ColorParser class to figure out the values of each color argument.
/// If the output argumentValue is float.NaN then the argument can still be valid, but
/// its actualy value cannot be determined.
/// </summary>
internal virtual bool GetColorArgumentValue(int argumentIndex, bool looseParsing, out float argumentValue)
{
argumentValue = 0;
FunctionArgument colorArgument = (argumentIndex >= 0 && argumentIndex < Arguments.Count)
? Arguments[argumentIndex] as FunctionArgument
: null;
// Make sure the argument has the right number of children
if (colorArgument == null ||
colorArgument.ArgumentItems.Count == 0 ||
(!looseParsing && colorArgument.ArgumentItems.Count != 1))
{
return(false);
}
ParseItem colorNumber = colorArgument.ArgumentItems[0];
UnitType unitType = PropertyValueHelpers.GetUnitType(colorNumber);
if (argumentIndex > 3)
{
// No color function has more than four arguments
return(false);
}
else if (argumentIndex == 3)
{
// It's the alpha value
if (ColorFunction == ColorFunctionType.Rgba || ColorFunction == ColorFunctionType.Hsla)
{
if (PropertyValueHelpers.IsValidNumber(colorNumber))
{
if (float.TryParse(colorNumber.Text, NumberStyles.Number, NumberFormatInfo.InvariantInfo, out argumentValue))
{
return(true);
}
}
}
}
else if (ColorFunction == ColorFunctionType.Rgb || ColorFunction == ColorFunctionType.Rgba)
{
// Red, Green, and Blue are always a <percentage> or <integer>
if (unitType == UnitType.Percentage)
{
if (float.TryParse(colorNumber.Text.TrimEnd('%'), NumberStyles.Number, NumberFormatInfo.InvariantInfo, out argumentValue))
{
argumentValue /= 100.0f;
return(true);
}
}
else if (PropertyValueHelpers.IsValidInteger(colorNumber))
{
if (int.TryParse(colorNumber.Text, out int intValue))
{
argumentValue = intValue / 255.0f;
return(true);
}
}
}
else if (argumentIndex == 0)
{
// Hue is always a <number>
if (PropertyValueHelpers.IsValidNumber(colorNumber))
{
if (float.TryParse(colorNumber.Text, NumberStyles.Number, NumberFormatInfo.InvariantInfo, out argumentValue))
{
argumentValue /= 360.0f;
return(true);
}
}
}
else
{
// Saturation and Lightness are always a percentage
if (unitType == UnitType.Percentage)
{
if (float.TryParse(colorNumber.Text.TrimEnd('%'), NumberStyles.Number, NumberFormatInfo.InvariantInfo, out argumentValue))
{
argumentValue /= 100.0f;
return(true);
}
}
}
return(false);
}